1
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Wood TR, Kucinski I, Voiculescu O. Distinct molecular profile of the chick organizer as a stem zone during axial elongation. Open Biol 2024; 14:240139. [PMID: 38955223 DOI: 10.1098/rsob.240139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 06/07/2024] [Indexed: 07/04/2024] Open
Abstract
The vertebrate organizer plays a crucial role in building the main (antero-posterior) axis of the embryo: it neuralizes the surrounding ectoderm, and is the site of emigration for cells making axial and paraxial mesendoderm during elongation. The chick organizer becomes a stem zone at the onset of elongation; it stops recruiting cells from the neighbouring ectoderm and generates all its derivatives from the small number of resident cells it contains at the end of gastrulation stages. Nothing is known about the molecular identity of this stem zone. Here, we specifically labelled long-term resident cells of the organizer and compared their RNA-seq profile to that of the neighbouring cell populations. Screening by reverse transcription-polymerase chain reaction and in situ hybridization identified four genes (WIF1, PTGDS, ThPO and UCKL1) that are upregulated only in the organizer region when it becomes a stem zone and remain expressed there during axial elongation. In experiments specifically labelling the resident cells of the mature organizer, we show that only these cells express these genes. These findings molecularly define the organizer as a stem zone and offer a key to understanding how this zone is set up, the molecular control of its cells' behaviour and the evolution of axial growth zones.
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Affiliation(s)
- Timothy R Wood
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Iwo Kucinski
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Octavian Voiculescu
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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2
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Lee HC, Oliveira NMM, Hastings C, Baillie-Benson P, Moverley AA, Lu HC, Zheng Y, Wilby EL, Weil TT, Page KM, Fu J, Moris N, Stern CD. Regulation of long-range BMP gradients and embryonic polarity by propagation of local calcium-firing activity. Nat Commun 2024; 15:1463. [PMID: 38368410 PMCID: PMC10874436 DOI: 10.1038/s41467-024-45772-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 02/02/2024] [Indexed: 02/19/2024] Open
Abstract
Many amniote vertebrate species including humans can form identical twins from a single embryo, but this only occurs rarely. It has been suggested that the primitive-streak-forming embryonic region emits signals that inhibit streak formation elsewhere but the signals involved, how they are transmitted and how they act has not been elucidated. Here we show that short tracks of calcium firing activity propagate through extraembryonic tissue via gap junctions and prevent ectopic primitive streak formation in chick embryos. Cross-regulation of calcium activity and an inhibitor of primitive streak formation (Bone Morphogenetic Protein, BMP) via NF-κB and NFAT establishes a long-range BMP gradient spanning the embryo. This mechanism explains how embryos of widely different sizes can maintain positional information that determines embryo polarity. We provide evidence for similar mechanisms in two different human embryo models and in Drosophila, suggesting an ancient evolutionary origin.
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Affiliation(s)
- Hyung Chul Lee
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
- School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, 77 Yongbong-ro, Gwangju, 61186, Korea.
| | - Nidia M M Oliveira
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- College of Professional Services, Murdoch University, 90 South St, Murdoch, WA, 6150, Australia
| | - Cato Hastings
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | | | - Adam A Moverley
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Cell and Developmental Biology, Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hui-Chun Lu
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
- Centre for Craniofacial & Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, Guy's Tower, London, SE1 9RT, UK
| | - Yi Zheng
- Departments of Mechanical Engineering, Biomedical Engineering, and Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
- BioInspired Syracuse Institute for Materials and Living Systems, Syracuse University, Syracuse, NY, USA
| | - Elise L Wilby
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Timothy T Weil
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Karen M Page
- Department of Mathematics, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jianping Fu
- Departments of Mechanical Engineering, Biomedical Engineering, and Cell & Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Naomi Moris
- The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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3
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Piatkowska AM, Adhikari K, Moverley AA, Turmaine M, Glazier JA, Plachta N, Evans SE, Stern CD. Sequential changes in cellular properties accompanying amniote somite formation. J Anat 2022; 242:417-435. [PMID: 36423208 PMCID: PMC9919497 DOI: 10.1111/joa.13791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/30/2022] [Accepted: 10/28/2022] [Indexed: 11/26/2022] Open
Abstract
Somites are transient structures derived from the pre-somitic mesoderm (PSM), involving mesenchyme-to-epithelial transition (MET) where the cells change their shape and polarize. Using Scanning electron microscopy (SEM), immunocytochemistry and confocal microscopy, we study the progression of these events along the tail-to-head axis of the embryo, which mirrors the progression of somitogenesis (younger cells located more caudally). SEM revealed that PSM epithelialization is a gradual process, which begins much earlier than previously thought, starting with the dorsalmost cells, then the medial ones, and then, simultaneously, the ventral and lateral cells, before a somite fully separates from the PSM. The core (internal) cells of the PSM and somites never epithelialize, which suggests that the core cells could be 'trapped' within the somitocoele after cells at the surfaces of the PSM undergo MET. Three-dimensional imaging of the distribution of the cell polarity markers PKCζ, PAR3, ZO1, the Golgi marker GM130 and the apical marker N-cadherin reveal that the pattern of polarization is distinctive for each marker and for each surface of the PSM, but the order of these events is not the same as the progression of cell elongation. These observations challenge some assumptions underlying existing models of somite formation.
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Affiliation(s)
- Agnieszka M. Piatkowska
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Kaustubh Adhikari
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK,Present address:
The Open UniversityMilton KeynesUK
| | - Adam A. Moverley
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Mark Turmaine
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - James A. Glazier
- Department of Intelligent Systems EngineeringBiocomplexity InstituteBloomingtonIndianaUSA
| | - Nicolas Plachta
- Department of Cell and Developmental Biology, 9‐123 Smilow Center for Translational Research, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Susan E. Evans
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
| | - Claudio D. Stern
- Department of Cell & Developmental BiologyUniversity College London, Gower Street (Anatomy Building)LondonUK
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4
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Lee HC, Fadaili Y, Stern CD. Molecular characteristics of the edge cells responsible for expansion of the chick embryo on the vitelline membrane. Open Biol 2022; 12:220147. [PMID: 36128719 PMCID: PMC9490332 DOI: 10.1098/rsob.220147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/23/2022] [Indexed: 11/12/2022] Open
Abstract
During early avian development, only a narrow band of cells (the edge cells, also called 'margin of overgrowth') at the rim of the embryo is responsible for blastoderm expansion by crawling over the vitelline membrane (VM) to cover the whole egg yolk in just 4 days (a process called epiboly). Surprisingly, this has not yet been studied in detail. Here we explore the edge cells of the chick embryo using in situ hybridization, immunohistochemistry and live imaging. Morphological and molecular properties reveal that the edge has a distinctive structure, being subdivided into sub-regions, including at least four distinct zones (which we name as leading, trailing, deep and stalk zones). This allows us to study reorganization of the edge region that accompanies reattachment of an explanted blastoderm to the VM. Immunohistochemistry uncovers distinct polarized cellular features resembling the process of collective cell migration described in other systems. Live imaging reveals dynamic lamellipodial and filopodial activity at the leading edge of the outermost cells. Our data provide evidence that edge cells are a distinct tissue. We propose that edge cells may be a useful model system for the study of wound healing and other closure events in epithelial cell sheets.
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Affiliation(s)
- Hyung Chul Lee
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Yara Fadaili
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Claudio D. Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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5
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Buzzi AL, Chen J, Thiery A, Delile J, Streit A. Sox8 remodels the cranial ectoderm to generate the ear. Proc Natl Acad Sci U S A 2022; 119:e2118938119. [PMID: 35867760 PMCID: PMC9282420 DOI: 10.1073/pnas.2118938119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
The vertebrate inner ear arises from a pool of progenitors with the potential to contribute to all the sense organs and cranial ganglia in the head. Here, we explore the molecular mechanisms that control ear specification from these precursors. Using a multiomics approach combined with loss-of-function experiments, we identify a core transcriptional circuit that imparts ear identity, along with a genome-wide characterization of noncoding elements that integrate this information. This analysis places the transcription factor Sox8 at the top of the ear determination network. Introducing Sox8 into the cranial ectoderm not only converts non-ear cells into ear progenitors but also activates the cellular programs for ear morphogenesis and neurogenesis. Thus, Sox8 has the unique ability to remodel transcriptional networks in the cranial ectoderm toward ear identity.
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Affiliation(s)
- Ailin Leticia Buzzi
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Jingchen Chen
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Alexandre Thiery
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Julien Delile
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
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6
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Lee HC, Hastings C, Stern CD. The extra-embryonic area opaca plays a role in positioning the primitive streak of the early chick embryo. Development 2022; 149:275748. [PMID: 35723262 PMCID: PMC9270967 DOI: 10.1242/dev.200303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 05/09/2022] [Indexed: 11/20/2022]
Abstract
Classical studies have established that the marginal zone, a ring of extra-embryonic epiblast immediately surrounding the embryonic epiblast (area pellucida) of the chick embryo, is important in setting embryonic polarity by positioning the primitive streak, the site of gastrulation. The more external extra-embryonic region (area opaca) was thought to have only nutritive and support functions. Using experimental embryology approaches, this study reveals three separable functions for this outer region. First, juxtaposition of the area opaca directly onto the area pellucida induces a new marginal zone from the latter; this induced domain is entirely posterior in character. Second, ablation and grafting experiments using an isolated anterior half of the blastoderm and pieces of area opaca suggest that the area opaca can influence the polarity of the adjacent marginal zone. Finally, we show that the loss of the ability of such isolated anterior half-embryos to regulate (re-establish polarity spontaneously) at the early primitive streak stage can be rescued by replacing the area opaca by one from a younger stage. These results uncover new roles of chick extra-embryonic tissues in early development. Summary: Two adjacent extra-embryonic tissues, the area opaca and the marginal zone, interact to influence the polarity of the early chick embryo.
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Affiliation(s)
- Hyung Chul Lee
- University College London Department of Cell and Developmental Biology , , Gower Street, London WC1E 6BT , UK
| | - Cato Hastings
- University College London Department of Cell and Developmental Biology , , Gower Street, London WC1E 6BT , UK
| | - Claudio D. Stern
- University College London Department of Cell and Developmental Biology , , Gower Street, London WC1E 6BT , UK
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7
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Lee HC, Hastings C, Oliveira NMM, Pérez-Carrasco R, Page KM, Wolpert L, Stern CD. 'Neighbourhood watch' model: embryonic epiblast cells assess positional information in relation to their neighbours. Development 2022; 149:275390. [PMID: 35438131 PMCID: PMC9188750 DOI: 10.1242/dev.200295] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/11/2022] [Indexed: 12/21/2022]
Abstract
In many developing and regenerating systems, tissue pattern is established through gradients of informative morphogens, but we know little about how cells interpret these. Using experimental manipulation of early chick embryos, including misexpression of an inducer (VG1 or ACTIVIN) and an inhibitor (BMP4), we test two alternative models for their ability to explain how the site of primitive streak formation is positioned relative to the rest of the embryo. In one model, cells read morphogen concentrations cell-autonomously. In the other, cells sense changes in morphogen status relative to their neighbourhood. We find that only the latter model can account for the experimental results, including some counter-intuitive predictions. This mechanism (which we name the ‘neighbourhood watch’ model) illuminates the classic ‘French Flag Problem’ and how positional information is interpreted by a sheet of cells in a large developing system. Summary: In a large developing system, the chick embryo before gastrulation, cells may interpret gradients of positional signals relative to their neighbours to position the primitive streak, establishing bilateral symmetry.
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Affiliation(s)
- Hyung Chul Lee
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Cato Hastings
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Nidia M M Oliveira
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Rubén Pérez-Carrasco
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Karen M Page
- Department of Mathematics, University College London, Gower Street, London WC1E 6BT, UK
| | - Lewis Wolpert
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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8
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Solovieva T, Lu HC, Moverley A, Plachta N, Stern CD. The embryonic node behaves as an instructive stem cell niche for axial elongation. Proc Natl Acad Sci U S A 2022. [PMID: 35101917 DOI: 10.1101/2020.11.10.376913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023] Open
Abstract
In warm-blooded vertebrate embryos (mammals and birds), the axial tissues of the body form from a growth zone at the tail end, Hensen's node, which generates neural, mesodermal, and endodermal structures along the midline. While most cells only pass through this region, the node has been suggested to contain a small population of resident stem cells. However, it is unknown whether the rest of the node constitutes an instructive niche that specifies this self-renewal behavior. Here, we use heterotopic transplantation of groups and single cells and show that cells not destined to enter the node can become resident and self-renew. Long-term resident cells are restricted to the posterior part of the node and single-cell RNA-sequencing reveals that the majority of these resident cells preferentially express G2/M phase cell-cycle-related genes. These results provide strong evidence that the node functions as a niche to maintain self-renewal of axial progenitors.
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Affiliation(s)
- Tatiana Solovieva
- Department of Cell and Developmental Biology, University College London, WC1E 6BT London, United Kingdom
| | - Hui-Chun Lu
- Department of Cell and Developmental Biology, University College London, WC1E 6BT London, United Kingdom
| | - Adam Moverley
- Department of Cell and Developmental Biology, University College London, WC1E 6BT London, United Kingdom
- Institute of Molecular Cell Biology, A*STAR, 138673 Proteos, Singapore
| | - Nicolas Plachta
- Institute of Molecular Cell Biology, A*STAR, 138673 Proteos, Singapore
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, WC1E 6BT London, United Kingdom;
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9
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The embryonic node behaves as an instructive stem cell niche for axial elongation. Proc Natl Acad Sci U S A 2022; 119:2108935119. [PMID: 35101917 PMCID: PMC8812687 DOI: 10.1073/pnas.2108935119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2021] [Indexed: 01/30/2023] Open
Abstract
Previous studies have suggested that the amniote node (Hensen’s node) contains a small population of self-renewing resident cells whose progeny progressively lay down axial tissues, including notochord and somites. This can only be demonstrated definitively at the level of single cells. Here we ask whether the node is an environment that can confer this behavior on cells that enter it. We challenge single cells in vivo and mRNA-profile these cells to demonstrate that the node can indeed do this, and thus show that the node acts as an instructive niche. In warm-blooded vertebrate embryos (mammals and birds), the axial tissues of the body form from a growth zone at the tail end, Hensen’s node, which generates neural, mesodermal, and endodermal structures along the midline. While most cells only pass through this region, the node has been suggested to contain a small population of resident stem cells. However, it is unknown whether the rest of the node constitutes an instructive niche that specifies this self-renewal behavior. Here, we use heterotopic transplantation of groups and single cells and show that cells not destined to enter the node can become resident and self-renew. Long-term resident cells are restricted to the posterior part of the node and single-cell RNA-sequencing reveals that the majority of these resident cells preferentially express G2/M phase cell-cycle–related genes. These results provide strong evidence that the node functions as a niche to maintain self-renewal of axial progenitors.
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10
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Lee HC, Oliveira NMM, Stern CD. Exploring the roles of FGF/MAPK and cVG1/GDF signalling on mesendoderm induction and convergent extension during chick primitive streak formation. Dev Genes Evol 2022; 232:115-123. [PMID: 36149507 PMCID: PMC9691481 DOI: 10.1007/s00427-022-00696-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/13/2022] [Indexed: 01/30/2023]
Abstract
During primitive streak formation in the chick embryo, cells undergo mesendoderm specification and convergent extension at the same time and in the same cells. Previous work has implicated cVG1 (GDF3) as a key factor for induction of primitive streak identity and positioning the primitive streak, whereas FGF signalling was implicated in regulating cell intercalation via regulation of components of the WNT-planar cell polarity (PCP) pathway. FGF has also been reported to be able to induce a primitive streak (but lacking the most axial derivatives such as notochord/prechordal mesendoderm). These signals emanate from different cell populations in the embryo, so how do they interact to ensure that the same cells undergo both cell intercalation and acquire primitive streak identity? Here we begin to address this question by examining in more detail the ability of the two classes of signals in regulating the two developmental events. Using misexpression of inducers and/or exposure to inhibitors and in situ hybridisation, we study how these two signals regulate expression of Brachyury (TBXT) and PRICKLE1 as markers for the primitive streak and the PCP, respectively. We find that both signals can induce both properties, but while FGF seems to be required for induction of the streak by cVG1, it is not necessary for induction of PRICKLE1. The results are consistent with cVG1 being a common regulator for both primitive streak identity and the initiation of convergent extension that leads to streak elongation.
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Affiliation(s)
- Hyung Chul Lee
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Nidia M. M. Oliveira
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - Claudio D. Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT UK
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11
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Lee HC, Lu HC, Turmaine M, Oliveira NMM, Yang Y, De Almeida I, Stern CD. Molecular anatomy of the pre-primitive-streak chick embryo. Open Biol 2020; 10:190299. [PMID: 32102607 PMCID: PMC7058932 DOI: 10.1098/rsob.190299] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/13/2020] [Indexed: 12/16/2022] Open
Abstract
The early stages of development of the chick embryo, leading to primitive streak formation (the start of gastrulation), have received renewed attention recently, especially for studies of the mechanisms of large-scale cell movements and those that position the primitive streak in the radial blastodisc. Over the long history of chick embryology, the terminology used to define different regions has been changing, making it difficult to relate studies to each other. To resolve this objectively requires precise definitions of the regions based on anatomical and functional criteria, along with a systematic molecular map that can be compared directly to the functional anatomy. Here, we undertake these tasks. We describe the characteristic cell morphologies (using scanning electron microscopy and immunocytochemistry for cell polarity markers) in different regions and at successive stages. RNAseq was performed for 12 regions of the blastodisc, from which a set of putative regional markers was selected. These were studied in detail by in situ hybridization. Together this provides a comprehensive resource allowing the community to define the regions unambiguously and objectively. In addition to helping with future experimental design and interpretation, this resource will also be useful for evolutionary comparisons between different vertebrate species.
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Affiliation(s)
| | | | | | | | | | | | - Claudio D. Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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12
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Tambalo M, Anwar M, Ahmed M, Streit A. Enhancer activation by FGF signalling during otic induction. Dev Biol 2020; 457:69-82. [PMID: 31539539 PMCID: PMC6902270 DOI: 10.1016/j.ydbio.2019.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/16/2019] [Accepted: 09/16/2019] [Indexed: 02/07/2023]
Abstract
Vertebrate ear progenitors are induced by fibroblast growth factor signalling, however the molecular mechanisms leading to the coordinate activation of downstream targets are yet to be discovered. The ear, like other sensory placodes, arises from the pre-placodal region at the border of the neural plate. Using a multiplex NanoString approach, we determined the response of these progenitors to FGF signalling by examining the changes of more than 200 transcripts that define the otic and other placodes, neural crest and neural plate territories. This analysis identifies new direct and indirect FGF targets during otic induction. Investigating changes in histone marks by ChIP-seq reveals that FGF exposure of pre-placodal cells leads to rapid deposition of active chromatin marks H3K27ac near FGF-response genes, while H3K27ac is depleted in the vicinity of non-otic genes. Genomic regions that gain H3K27ac act as cis-regulatory elements controlling otic gene expression in time and space and define a unique transcription factor signature likely to control their activity. Finally, we show that in response to FGF signalling the transcription factor dimer AP1 recruits the histone acetyl transferase p300 to selected otic enhancers. Thus, during ear induction FGF signalling modifies the chromatin landscape to promote enhancer activation and chromatin accessibility.
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Affiliation(s)
- Monica Tambalo
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Maryam Anwar
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Mohi Ahmed
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK.
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13
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Prajapati RS, Hintze M, Streit A. PRDM1 controls the sequential activation of neural, neural crest and sensory progenitor determinants. Development 2019; 146:dev.181107. [PMID: 31806661 DOI: 10.1242/dev.181107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 11/27/2019] [Indexed: 12/25/2022]
Abstract
During early embryogenesis, the ectoderm is rapidly subdivided into neural, neural crest and sensory progenitors. How the onset of lineage determinants and the loss of pluripotency markers are temporally and spatially coordinated in vivo is still debated. Here, we identify a crucial role for the transcription factor PRDM1 in the orderly transition from epiblast to defined neural lineages in chick. PRDM1 is initially expressed broadly in the entire epiblast, but becomes gradually restricted as cell fates are specified. We find that PRDM1 is required for the loss of some pluripotency markers and the onset of neural, neural crest and sensory progenitor specifier genes. PRDM1 directly activates their expression by binding to their promoter regions and recruiting the histone demethylase Kdm4a to remove repressive histone marks. However, once neural lineage determinants become expressed, they in turn repress PRDM1, whereas prolonged PRDM1 expression inhibits neural, neural crest and sensory progenitor genes, suggesting that its downregulation is necessary for cells to maintain their identity. Therefore, PRDM1 plays multiple roles during ectodermal cell fate allocation.
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Affiliation(s)
- Ravindra S Prajapati
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Mark Hintze
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
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14
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15
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Bauer R, Tondl P, Schneider WJ. A differentiation program induced by bone morphogenetic proteins 4 and 7 in endodermal epithelial cells provides the molecular basis for efficient nutrient transport by the chicken yolk sac. Dev Dyn 2019; 249:222-236. [PMID: 31691430 PMCID: PMC7028021 DOI: 10.1002/dvdy.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The mammalian yolk sac provides nutrients for the growing fetus during critical early developmental processes such as neural tube closure, which precedes the functional maturation of the placenta. In contrast, oviparous species such as the chicken rely solely on the yolk sac for transfer of nutrients from the yolk to the developing embryo. However, the molecular mechanisms that provide the yolk sac with nutrient transfer competence remain poorly understood. RESULTS We demonstrate that the chicken endodermal epithelial cells (EEC), which are in close contact with the yolk, gain their nutrient-transport competence by a paracrine crosstalk with the blood-vessel forming mesodermal cell layer. Bone morphogenetic proteins (BMP) 4 and 7 produced by ectodermal and mesodermal cell layers likely initiate a differentiation program of EECs during the transition from the area vitellina to the area vasculosa. BMPs, by inducing SMAD signaling, promote the up-regulation of endocytic receptor expression and thereby provide the EECs with the molecular machinery to produce triglyceride-rich lipoprotein particles. CONCLUSION This paracrine signaling cascade may constitute the basis for the EEC-mediated mechanism underlying the efficient uptake, degradation, resynthesis, and transfer of yolk-derived nutrients into the embryonic circulation, which assures proper energy supply and development of the growing fetus.
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Affiliation(s)
- Raimund Bauer
- Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Medical University of Vienna, Vienna, Austria
| | - Philipp Tondl
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Wolfgang J Schneider
- Department of Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Vienna, Austria
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16
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Transplantation of Neural Tissue: Quail-Chick Chimeras. Methods Mol Biol 2019. [PMID: 31552671 DOI: 10.1007/978-1-4939-9732-9_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Tissue transplantation is an important approach in developmental neurobiology to determine cell fate, to uncover inductive interactions required for tissue specification and patterning as well as to establish tissue competence and commitment. Combined with state-of-the-art molecular approaches, transplantation assays have been instrumental for the discovery of gene regulatory networks controlling cell fate choices and how such networks change over time. Avian species are among the favorite model systems for these approaches because of their accessibility and relatively large size. Here we describe two culture techniques used to generate quail-chick chimeras at different embryonic stages and methods to distinguish graft and donor tissue.
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17
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Osório L, Wu X, Wang L, Jiang Z, Neideck C, Sheng G, Zhou Z. ISM1 regulates NODAL signaling and asymmetric organ morphogenesis during development. J Cell Biol 2019; 218:2388-2402. [PMID: 31171630 PMCID: PMC6605798 DOI: 10.1083/jcb.201801081] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/24/2019] [Accepted: 05/06/2019] [Indexed: 12/14/2022] Open
Abstract
Isthmin1 (ISM1) was originally identified as a fibroblast group factor expressed in Xenopus laevis embryonic brain, but its biological functions remain unclear. The spatiotemporal distribution of ISM1, with high expression in the anterior primitive streak of the chick embryo and the anterior mesendoderm of the mouse embryo, suggested that ISM1 may regulate signaling by the NODAL subfamily of TGB-β cytokines that control embryo patterning. We report that ISM1 is an inhibitor of NODAL signaling. ISM1 has little effect on TGF-β1, ACTIVIN-A, or BMP4 signaling but specifically inhibits NODAL-induced phosphorylation of SMAD2. In line with this observation, ectopic ISM1 causes defective left-right asymmetry and abnormal heart positioning in chick embryos. Mechanistically, ISM1 interacts with NODAL ligand and type I receptor ACVR1B through its AMOP domain, which compromises the NODAL-ACVR1B interaction and down-regulates phosphorylation of SMAD2. Therefore, we identify ISM1 as an extracellular antagonist of NODAL and reveal a negative regulatory mechanism that provides greater plasticity for the fine-tuning of NODAL signaling.
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Affiliation(s)
- Liliana Osório
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Xuewei Wu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Linsheng Wang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Zhixin Jiang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Carlos Neideck
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
| | - Guojun Sheng
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan.,RIKEN Center for Developmental Biology, Kobe, Japan
| | - Zhongjun Zhou
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong .,Shenzhen Institute of Innovation and Research, The University of Hong Kong, Nanshan, Shenzhen, China
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18
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Martyn I, Kanno TY, Brivanlou AH. Chick Models and Human-Chick Organizer Grafts. Methods Mol Biol 2019; 2005:77-89. [PMID: 31175647 DOI: 10.1007/978-1-4939-9524-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The combination of affordability, large size, and ease of access at almost every stage of development renders the chick an excellent model organism for studying vertebrate development. Not only is it a great system in and of itself, but these qualities make it a great host for interspecies chimera experiments. In this chapter we highlight some notable examples of mammalian-chick chimeras, and show how one can for instance use the chick to push mammalian stem cell experiments further to learn about the behavior and capabilities of these cells in vivo. In particular, here we present the methodology necessary for transplantation of human embryonic stem cell (hESC)-derived "gastruloids" stimulated to generate a human organizer into the chick embryo. In these human-chick chimeras, the human organizer cells self-organize to contribute directly to notochord-like tissue and indirectly induce host chick cells to generate neural tissue.
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Affiliation(s)
- Iain Martyn
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, New York, NY, USA
- Center for Studies in Physics and Biology, The Rockefeller University, New York, NY, USA
| | - Tatiane Y Kanno
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, New York, NY, USA
| | - Ali H Brivanlou
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, New York, NY, USA.
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19
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Neural induction by the node and placode induction by head mesoderm share an initial state resembling neural plate border and ES cells. Proc Natl Acad Sci U S A 2017; 115:355-360. [PMID: 29259119 DOI: 10.1073/pnas.1719674115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Around the time of gastrulation in higher vertebrate embryos, inductive interactions direct cells to form central nervous system (neural plate) or sensory placodes. Grafts of different tissues into the periphery of a chicken embryo elicit different responses: Hensen's node induces a neural plate whereas the head mesoderm induces placodes. How different are these processes? Transcriptome analysis in time course reveals that both processes start by induction of a common set of genes, which later diverge. These genes are remarkably similar to those induced by an extraembryonic tissue, the hypoblast, and are normally expressed in the pregastrulation stage epiblast. Explants of this epiblast grown in the absence of further signals develop as neural plate border derivatives and eventually express lens markers. We designate this state as "preborder"; its transcriptome resembles embryonic stem cells. Finally, using sequential transplantation experiments, we show that the node, head mesoderm, and hypoblast are interchangeable to begin any of these inductions while the final outcome depends on the tissue emitting the later signals.
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20
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Schock EN, Brugmann SA. Neural crest cells utilize primary cilia to regulate ventral forebrain morphogenesis via Hedgehog-dependent regulation of oriented cell division. Dev Biol 2017; 431:168-178. [PMID: 28941984 DOI: 10.1016/j.ydbio.2017.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/20/2017] [Accepted: 09/19/2017] [Indexed: 12/18/2022]
Abstract
Development of the brain directly influences the development of the face via both physical growth and Sonic hedgehog (SHH) activity; however, little is known about how neural crest cells (NCCs), the mesenchymal population that comprise the developing facial prominences, influence the development of the brain. We utilized the conditional ciliary mutant Wnt1-Cre;Kif3afl/fl to demonstrate that loss of primary cilia on NCCs resulted in a widened ventral forebrain. We found that neuroectodermal Shh expression, dorsal/ventral patterning, and amount of proliferation in the ventral neuroectoderm was not changed in Wnt1-Cre;Kif3afl/fl mutants; however, tissue polarity and directional cell division were disrupted. Furthermore, NCCs of Wnt1-Cre;Kif3afl/fl mutants failed to respond to a SHH signal emanating from the ventral forebrain. We were able to recapitulate the ventral forebrain phenotype by removing Smoothened from NCCs (Wnt1-Cre;Smofl/fl) indicating that changes in the ventral forebrain were mediated through a Hedgehog-dependent mechanism. Together, these data suggest a novel, cilia-dependent mechanism for NCCs during forebrain development.
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Affiliation(s)
- Elizabeth N Schock
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Samantha A Brugmann
- Division of Plastic Surgery, Department of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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21
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Hintze M, Prajapati RS, Tambalo M, Christophorou NAD, Anwar M, Grocott T, Streit A. Cell interactions, signals and transcriptional hierarchy governing placode progenitor induction. Development 2017; 144:2810-2823. [PMID: 28684624 PMCID: PMC5560042 DOI: 10.1242/dev.147942] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 06/21/2017] [Indexed: 12/18/2022]
Abstract
In vertebrates, cranial placodes contribute to all sense organs and sensory ganglia and arise from a common pool of Six1/Eya2+ progenitors. Here we dissect the events that specify ectodermal cells as placode progenitors using newly identified genes upstream of the Six/Eya complex. We show in chick that two different tissues, namely the lateral head mesoderm and the prechordal mesendoderm, gradually induce placode progenitors: cells pass through successive transcriptional states, each identified by distinct factors and controlled by different signals. Both tissues initiate a common transcriptional state but over time impart regional character, with the acquisition of anterior identity dependent on Shh signalling. Using a network inference approach we predict the regulatory relationships among newly identified transcription factors and verify predicted links in knockdown experiments. Based on this analysis we propose a new model for placode progenitor induction, in which the initial induction of a generic transcriptional state precedes regional divergence.
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Affiliation(s)
- Mark Hintze
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Ravindra Singh Prajapati
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Monica Tambalo
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Nicolas A D Christophorou
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Maryam Anwar
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Timothy Grocott
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Andrea Streit
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
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22
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A gene network regulated by FGF signalling during ear development. Sci Rep 2017; 7:6162. [PMID: 28733657 DOI: 10.1038/s41598-017-05472-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 05/31/2017] [Indexed: 02/08/2023] Open
Abstract
During development cell commitment is regulated by inductive signals that are tightly controlled in time and space. In response, cells activate specific programmes, but the transcriptional circuits that maintain cell identity in a changing signalling environment are often poorly understood. Specification of inner ear progenitors is initiated by FGF signalling. Here, we establish the genetic hierarchy downstream of FGF by systematic analysis of many ear factors combined with a network inference approach. We show that FGF rapidly activates a small circuit of transcription factors forming positive feedback loops to stabilise otic progenitor identity. Our predictive network suggests that subsequently, transcriptional repressors ensure the transition of progenitors to mature otic cells, while simultaneously repressing alternative fates. Thus, we reveal the regulatory logic that initiates ear formation and highlight the hierarchical organisation of the otic gene network.
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23
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Chen J, Tambalo M, Barembaum M, Ranganathan R, Simões-Costa M, Bronner ME, Streit A. A systems-level approach reveals new gene regulatory modules in the developing ear. Development 2017; 144:1531-1543. [PMID: 28264836 PMCID: PMC5399671 DOI: 10.1242/dev.148494] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/24/2017] [Indexed: 01/23/2023]
Abstract
The inner ear is a complex vertebrate sense organ, yet it arises from a simple epithelium, the otic placode. Specification towards otic fate requires diverse signals and transcriptional inputs that act sequentially and/or in parallel. Using the chick embryo, we uncover novel genes in the gene regulatory network underlying otic commitment and reveal dynamic changes in gene expression. Functional analysis of selected transcription factors reveals the genetic hierarchy underlying the transition from progenitor to committed precursor, integrating known and novel molecular players. Our results not only characterize the otic transcriptome in unprecedented detail, but also identify new gene interactions responsible for inner ear development and for the segregation of the otic lineage from epibranchial progenitors. By recapitulating the embryonic programme, the genes and genetic sub-circuits discovered here might be useful for reprogramming naïve cells towards otic identity to restore hearing loss. Summary: Transcriptome analysis and knock down of select transcription factors reveals a genetic hierarchy as cells become committed to inner ear fate.
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Affiliation(s)
- Jingchen Chen
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Monica Tambalo
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Meyer Barembaum
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ramya Ranganathan
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
| | - Marcos Simões-Costa
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Andrea Streit
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK
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24
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De Almeida I, Oliveira NMM, Randall RA, Hill CS, McCoy JM, Stern CD. Calreticulin is a secreted BMP antagonist, expressed in Hensen's node during neural induction. Dev Biol 2017; 421:161-170. [PMID: 27919666 PMCID: PMC5231319 DOI: 10.1016/j.ydbio.2016.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 11/27/2022]
Abstract
Hensen's node is the "organizer" of the avian and mammalian early embryo. It has many functions, including neural induction and patterning of the ectoderm and mesoderm. Some of the signals responsible for these activities are known but these do not explain the full complexity of organizer activity. Here we undertake a functional screen to discover new secreted factors expressed by the node at this time of development. Using a Signal Sequence Trap in yeast, we identify several candidates. Here we focus on Calreticulin. We show that in addition to its known functions in intracellular Calcium regulation and protein folding, Calreticulin is secreted, it can bind to BMP4 and act as a BMP antagonist in vivo and in vitro. Calreticulin is not sufficient to account for all organizer functions but may contribute to the complexity of its activity.
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Affiliation(s)
- Irene De Almeida
- Department of Cell & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Nidia M M Oliveira
- Department of Cell & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | | | | | | | - Claudio D Stern
- Department of Cell & Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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25
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Anderson C, Khan MAF, Wong F, Solovieva T, Oliveira NMM, Baldock RA, Tickle C, Burt DW, Stern CD. A strategy to discover new organizers identifies a putative heart organizer. Nat Commun 2016; 7:12656. [PMID: 27557800 DOI: 10.1038/ncomms12656] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/19/2016] [Indexed: 11/09/2022] Open
Abstract
Organizers are regions of the embryo that can both induce new fates and impart pattern on other regions. So far, surprisingly few organizers have been discovered, considering the number of patterned tissue types generated during development. This may be because their discovery has relied on transplantation and ablation experiments. Here we describe a new approach, using chick embryos, to discover organizers based on a common gene expression signature, and use it to uncover the anterior intestinal portal (AIP) endoderm as a putative heart organizer. We show that the AIP can induce cardiac identity from non-cardiac mesoderm and that it can pattern this by specifying ventricular and suppressing atrial regional identity. We also uncover some of the signals responsible. The method holds promise as a tool to discover other novel organizers acting during development.
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Affiliation(s)
- Claire Anderson
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Mohsin A F Khan
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Frances Wong
- Department of Genomics and Genetics, The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG Scotland, UK
| | - Tatiana Solovieva
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Nidia M M Oliveira
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Richard A Baldock
- Biomedical Systems Analysis Section, MRC Human Genetics Unit, IGMM, University of Edinburgh, Crewe Road, Edinburgh, EH4 2XU, UK
| | - Cheryll Tickle
- Department of Biology &Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Dave W Burt
- Department of Genomics and Genetics, The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG Scotland, UK
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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26
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Langenbacher AD, De Tomaso AW. Temporally and spatially dynamic germ cell niches in Botryllus schlosseri revealed by expression of a TGF-beta family ligand and vasa. EvoDevo 2016; 7:9. [PMID: 27073614 PMCID: PMC4828856 DOI: 10.1186/s13227-016-0047-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/30/2016] [Indexed: 02/04/2023] Open
Abstract
Background Germ cells are specified during early development and are responsible for generating gametes in the adult. After germ cells are specified, they typically migrate to a particular niche in the organism where they reside for the remainder of its lifetime. For some model organisms, the specification and migration of germ cells have been extensively studied, but how these events occur in animals that reproduce both sexually and asexually is not well understood. Results We have identified a novel TGF-β family member in Botryllus schlosseri, tgfβ-f, and found that it is expressed by follicle cell progenitors and the differentiated follicle and support cells surrounding the maturing gametes. Using the expression of tgfβ-f and the germ cell marker vasa, we have found that nearly all germ cells in Botryllus are associated with tgfβ-f-expressing follicle progenitors in clusters consisting solely of those two cell types. These clusters were mostly small, consisting of ten or fewer cells, and generally contained between a 2:1 and 1:1 ratio of follicle progenitors to germ cells. Clusters of germ and follicle progenitor cells were primarily localized to niches in the primary and secondary buds, but could also be found in other locations including the vasculature. We analyzed the location of germ cell clusters throughout the asexual life cycle of Botryllus and found that at the stage when germ cells are first detected in the secondary bud niche, a dramatic change in the size and location of germ/follicle cell clusters also occurred. Conclusions Our findings suggest that germ/follicle cell clusters have predictable migratory patterns during the weekly asexual developmental cycle in Botryllus. An increased number of small clusters and the presence of clusters in the vasculature coinciding with the appearance of clusters in the secondary bud suggest that fragmentation of clusters and the migration of smaller clusters through the vasculature may be an important aspect of Botryllus reproductive biology, ensuring the transmission of the germline to subsequent asexual generations. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0047-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam D Langenbacher
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106-9610 USA ; Department of MCD Biology, UCLA, Los Angeles, CA 90095 USA
| | - Anthony W De Tomaso
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106-9610 USA
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27
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Shida H, Mende M, Takano-Yamamoto T, Osumi N, Streit A, Wakamatsu Y. Otic placode cell specification and proliferation are regulated by Notch signaling in avian development. Dev Dyn 2015; 244:839-51. [PMID: 25970828 DOI: 10.1002/dvdy.24291] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 04/26/2015] [Accepted: 05/01/2015] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND The entire inner ear including the cochlear-vestibular ganglion arises from a simple epithelium, the otic placode. Precursors for the placode originate from a pool of progenitors located in ectoderm next to the future hindbrain, the pre-otic field, where they are intermingled with future epibranchial and epidermal cells. While the importance of secreted proteins, such as FGFs and Wnts, in imparting otic identity has been well studied, how precursors for these different fates segregate locally is less well understood. RESULTS (1) The Notch ligand Delta1 and the Notch target Hes5-2 are expressed in a part of pre-otic field before otic commitment, indicative of active Notch signaling, and this is confirmed using a Notch reporter. (2) Loss and gain-of-function approaches reveal that Notch signaling regulates both proliferation and specification of pre-otic progenitors. CONCLUSIONS Our results identify a novel function of Notch signaling in cell fate determination in the pre-otic field of avian embryos.
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Affiliation(s)
- Hiroko Shida
- Department of Developmental Neuroscience, Center for Translational and Advanced Animal Research, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, Miyagi, Japan
| | - Michael Mende
- Department of Craniofacial Development and Stem Cell Biology, King's College London
| | - Teruko Takano-Yamamoto
- Division of Orthodontics and Dentofacial Orthopedics, Tohoku University Graduate School of Dentistry, Miyagi, Japan
| | - Noriko Osumi
- Department of Developmental Neuroscience, Center for Translational and Advanced Animal Research, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Andrea Streit
- Department of Craniofacial Development and Stem Cell Biology, King's College London
| | - Yoshio Wakamatsu
- Department of Developmental Neuroscience, Center for Translational and Advanced Animal Research, Tohoku University Graduate School of Medicine, Miyagi, Japan
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28
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Fixation/permeabilization procedure for mRNA in situ hybridization of zebrafish whole-mount oocytes, embryos, and larvae. Methods Mol Biol 2015; 1211:1-13. [PMID: 25218372 DOI: 10.1007/978-1-4939-1459-3_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
A new procedure for improved in situ hybridization of zebrafish whole-mount oocytes, embryos, and early larvae is described. The procedure relies on the simultaneous fixation/permeabilization of samples using formaldehyde as fixative and short C-chain aliphatic carboxylic acids, particularly glacial acetic acid, as permeabilizers. As compared with in situ hybridization performed with routine methods, our procedure is simpler and provides better structural preservation of cells and tissues, equivalent mRNA signals, and similar results in embryos of different developmental stages. It is hypothesized that during aldehyde fixation short C-chain aliphatic carboxylic acids modulate the rate of formation and/or destruction of methylene bridges established between cell proteins.
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29
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Sánchez-Arrones L, Ferrán JL, Hidalgo-Sanchez M, Puelles L. Origin and early development of the chicken adenohypophysis. Front Neuroanat 2015; 9:7. [PMID: 25741242 PMCID: PMC4330794 DOI: 10.3389/fnana.2015.00007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/12/2015] [Indexed: 01/06/2023] Open
Abstract
The adenohypophysis (ADH) is an important endocrine organ involved in the regulation of many physiological processes. The late morphogenesis of this organ at neural tube stages is well known: the epithelial ADH primordium is recognized as an invagination of the stomodeal roof (Rathke’s pouch), whose walls later thicken and differentiate as the primordium becomes pediculated, and then fully separated from the stomodeum. The primordium attaches to the pial surface of the basal hypothalamus, next to the neurohypophyseal field (NH; future posterior pituitary), from which it was previously separated by migrating prechordal plate (pp) cells. Once the NH evaginates, the ADH surrounds it and jointly forms with it the pituitary gland. In contrast, little is known about the precise origin of the ADH precursors at neural plate stages and how the primordium reaches the stomodeum. For that reason, we produced in the chicken a specific ADH fate map at early neural plate stages, which was amplified with gene markers. By means of experiments labeling the mapped presumptive ADH, we were able to follow the initial anlage into its transformation into Rathke’s pouch. The ADH origin was corroborated to be strictly extraneural, i.e., to lie at stage HH4/5 outside of the anterior neural plate (anp) within the pre-placodal field. The ADH primordium is fully segregated from the anterior neural border cells and the neighboring olfactory placodes both in terms of precursor cells and molecular profile from head fold stages onwards. The placode becomes visible as a molecularly characteristic ectodermal thickening from stage HH10 onwards. The onset of ADH genoarchitectonic regionalization into intermediate and anterior lobes occurs at closed neural tube stages.
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Affiliation(s)
- Luisa Sánchez-Arrones
- Faculty of Medicine, Department of Human Anatomy, School of Medicine and IMIB (Instiuto Murciano de Investigación Biosanitaria), University of Murcia Murcia, Spain
| | - José L Ferrán
- Faculty of Medicine, Department of Human Anatomy, School of Medicine and IMIB (Instiuto Murciano de Investigación Biosanitaria), University of Murcia Murcia, Spain
| | - Matías Hidalgo-Sanchez
- Department of Cell Biology, Faculty of Science, University of Extremadura Badajoz, Spain
| | - Luis Puelles
- Faculty of Medicine, Department of Human Anatomy, School of Medicine and IMIB (Instiuto Murciano de Investigación Biosanitaria), University of Murcia Murcia, Spain
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30
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Yan B, Neilson KM, Ranganathan R, Maynard T, Streit A, Moody SA. Microarray identification of novel genes downstream of Six1, a critical factor in cranial placode, somite, and kidney development. Dev Dyn 2014; 244:181-210. [PMID: 25403746 DOI: 10.1002/dvdy.24229] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 11/03/2014] [Accepted: 11/12/2014] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Six1 plays an important role in the development of several vertebrate organs, including cranial sensory placodes, somites, and kidney. Although Six1 mutations cause one form of branchio-otic syndrome (BOS), the responsible gene in many patients has not been identified; genes that act downstream of Six1 are potential BOS candidates. RESULTS We sought to identify novel genes expressed during placode, somite and kidney development by comparing gene expression between control and Six1-expressing ectodermal explants. The expression patterns of 19 of the significantly up-regulated and 11 of the significantly down-regulated genes were assayed from cleavage to larval stages. A total of 28/30 genes are expressed in the otocyst, a structure that is functionally disrupted in BOS, and 26/30 genes are expressed in the nephric mesoderm, a structure that is functionally disrupted in the related branchio-otic-renal (BOR) syndrome. We also identified the chick homologues of five genes and show that they have conserved expression patterns. CONCLUSIONS Of the 30 genes selected for expression analyses, all are expressed at many of the developmental times and appropriate tissues to be regulated by Six1. Many have the potential to play a role in the disruption of hearing and kidney function seen in BOS/BOR patients.
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Affiliation(s)
- Bo Yan
- Department of Anatomy and Regenerative Biology, The George Washington University, School of Medicine and Health Sciences, Washington, DC
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31
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Torlopp A, Khan MAF, Oliveira NMM, Lekk I, Soto-Jiménez LM, Sosinsky A, Stern CD. The transcription factor Pitx2 positions the embryonic axis and regulates twinning. eLife 2014; 3:e03743. [PMID: 25496870 PMCID: PMC4371885 DOI: 10.7554/elife.03743] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 11/14/2014] [Indexed: 12/29/2022] Open
Abstract
Embryonic polarity of invertebrates, amphibians and fish is specified largely by maternal determinants, which fixes cell fates early in development. In contrast, amniote embryos remain plastic and can form multiple individuals until gastrulation. How is their polarity determined? In the chick embryo, the earliest known factor is cVg1 (homologous to mammalian growth differentiation factor 1, GDF1), a transforming growth factor beta (TGFβ) signal expressed posteriorly before gastrulation. A molecular screen to find upstream regulators of cVg1 in normal embryos and in embryos manipulated to form twins now uncovers the transcription factor Pitx2 as a candidate. We show that Pitx2 is essential for axis formation, and that it acts as a direct regulator of cVg1 expression by binding to enhancers within neighbouring genes. Pitx2, Vg1/GDF1 and Nodal are also key actors in left-right asymmetry, suggesting that the same ancient polarity determination mechanism has been co-opted to different functions during evolution.
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Affiliation(s)
- Angela Torlopp
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
| | - Mohsin A F Khan
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
| | - Nidia M M Oliveira
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
| | - Ingrid Lekk
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
| | - Luz Mayela Soto-Jiménez
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
- Programa de Ciencias
Genómicas, Universidad Nacional Autónoma de
México, Morelos, Mexico
| | - Alona Sosinsky
- Institute of Structural
and Molecular Biology, Birkbeck College, University of
London, London, United Kingdom
| | - Claudio D Stern
- Department of Cell and
Developmental Biology, University College
London, London, United Kingdom
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32
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Transcriptome analysis of chicken ES, blastodermal and germ cells reveals that chick ES cells are equivalent to mouse ES cells rather than EpiSC. Stem Cell Res 2014; 14:54-67. [PMID: 25514344 PMCID: PMC4305369 DOI: 10.1016/j.scr.2014.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 12/21/2022] Open
Abstract
Pluripotent Embryonic Stem cell (ESC) lines can be derived from a variety of sources. Mouse lines derived from the early blastocyst and from primordial germ cells (PGCs) can contribute to all somatic lineages and to the germ line, whereas cells from slightly later embryos (EpiSC) no longer contribute to the germ line. In chick, pluripotent ESCs can be obtained from PGCs and from early blastoderms. Established PGC lines and freshly isolated blastodermal cells (cBC) can contribute to both germinal and somatic lineages but established lines from the former (cESC) can only produce somatic cell types. For this reason, cESCs are often considered to be equivalent to mouse EpiSC. To define these cell types more rigorously, we have performed comparative microarray analysis to describe a transcriptomic profile specific for each cell type. This is validated by real time RT-PCR and in situ hybridisation. We find that both cES and cBC cells express classic pluripotency-related genes (including cPOUV/OCT4, NANOG, SOX2/3, KLF2 and SALL4), whereas expression of DAZL, DND1, DDX4 and PIWIL1 defines a molecular signature for germ cells. Surprisingly, contrary to the prevailing view, our results also suggest that cES cells resemble mouse ES cells more closely than mouse EpiSC.
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Langenbacher AD, Rodriguez D, Di Maio A, De Tomaso AW. Whole-mount fluorescent in situ hybridization staining of the colonial tunicate Botryllus schlosseri. Genesis 2014; 53:194-201. [PMID: 25179474 DOI: 10.1002/dvg.22820] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 01/23/2023]
Abstract
Botryllus schlosseri is a colonial ascidian with characteristics that make it an attractive model for studying immunology, stem cell biology, evolutionary biology, and regeneration. Transcriptome sequencing and the recent completion of a draft genome sequence for B. schlosseri have revealed a large number of genes, both with and without vertebrate homologs, but analyzing the spatial and temporal expression of these genes in situ has remained a challenge. Here, we report a robust protocol for in situ hybridization that enables the simultaneous detection of multiple transcripts in whole adult B. schlosseri using Tyramide Signal Amplification in conjunction with digoxigenin- and dinitrophenol-labeled RNA probes. Using this protocol, we have identified a number of genes that can serve as markers for developing and mature structures in B. schlosseri, permitting analysis of phenotypes induced in loss-of-function experiments.
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Affiliation(s)
- Adam D Langenbacher
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, California
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Voiculescu O, Bodenstein L, Lau IJ, Stern CD. Local cell interactions and self-amplifying individual cell ingression drive amniote gastrulation. eLife 2014; 3:e01817. [PMID: 24850665 PMCID: PMC4029171 DOI: 10.7554/elife.01817] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Gastrulation generates three layers of cells (ectoderm, mesoderm, endoderm) from a single sheet, while large scale cell movements occur across the entire embryo. In amniote (reptiles, birds, mammals) embryos, the deep layers arise by epithelial-to-mesenchymal transition (EMT) at a morphologically stable midline structure, the primitive streak (PS). We know very little about how these events are controlled or how the PS is maintained despite its continuously changing cellular composition. Using the chick, we show that isolated EMT events and ingression of individual cells start well before gastrulation. A Nodal-dependent ‘community effect’ then concentrates and amplifies EMT by positive feedback to form the PS as a zone of massive cell ingression. Computer simulations show that a combination of local cell interactions (EMT and cell intercalation) is sufficient to explain PS formation and the associated complex movements globally across a large epithelial sheet, without the need to invoke long-range signalling. DOI:http://dx.doi.org/10.7554/eLife.01817.001 A key process during the development of an embryo involves a single layer of cells reorganizing into three ‘germ layers’: the ectoderm, which becomes the skin and nervous system; the mesoderm, which gives rise to the skeleton, muscles and the circulatory and urinogenital systems, and the endoderm, which gives rise to the lining of the gut and associated organs. The process of forming these three layers is known as gastrulation. To date most experiments on gastrulation in vertebrates have been performed on frog embryos. However, the embryos of amniotes, the group of ‘higher’ vertebrates that comprises reptiles, birds and mammals, differ from those of frogs in a number of ways. Now Voiculescu et al. have used a combination of experimental and computational techniques to shed new light on gastrulation in chick embryos. Just prior to gastrulation, the cells of the amniote embryo are arranged in a flat disk, one cell thick, called the epiblast. The cells of the epiblast then move to form the mesoderm and endoderm (in a process called epithelial-to-mesenchymal transition). These cell movements also lead to the formation of a structure called the primitive streak that establishes the left-right symmetry of the organism, and also defines the midline of the body. Now Voiculescu et al. have shown that the epithelial-to-mesenchymal transition starts before the primitive streak appears, and that two main processes drive gastrulation. One involves cells inserting themselves between other cells at the midline of the epiblast, which causes a double whorl-like movement within the plane of the epiblast. At the same time small numbers of cells leave the epiblast, and as these cells accumulate under the epiblast, they initiate a positive feedback effect by which they encourage more cells to leave the epiblast. Voiculescu et al. found that this ‘community effect’ involves signalling by a protein called Nodal. This protein effectively amplifies the epithelial-to-mesenchymal transition and leads to the appearance of the primitive streak at the midline. Using computational modelling, Voiculescu et al. argue that the movements of gastrulation can be explained entirely based on local interactions between cells, without the need for cells to send signals over long distances to guide cell movements, as had been generally believed. DOI:http://dx.doi.org/10.7554/eLife.01817.002
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Affiliation(s)
- Octavian Voiculescu
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Lawrence Bodenstein
- Division of Pediatric Surgery, Morgan Stanley Children's Hospital of New York-Presbyterian, New York, United States Department of Surgery, College of Physicians and Surgeons, Columbia University, New York, United States
| | - I-Jun Lau
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Claudio D Stern
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Wakai S, Shibuki Y, Yokozawa K, Nakamura S, Adegawa Y, Yoshida A, Tsuta K, Furuta K. Recycling and long-term storage of fluorescence in situ hybridization slides. Am J Clin Pathol 2014; 141:374-80. [PMID: 24515765 DOI: 10.1309/ajcpyx1uti7ldauy] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
OBJECTIVES Although fluorescence in situ hybridization (FISH) technology is adequate, demand exists for additional recycling and long-term storage of FISH slides. METHODS Formalin-fixed paraffin-embedded slides derived from breast cancer cases were used for this study. Each slide was probed, and then procedures for removing probes were performed, such as removing the fluorescent probe and diamidino-2-phenylindole signals. Formamide was used for removing probes, and then slides were stored dry at room temperature (22°C), 4°C, -20°C, or -80°C for 101 days. Following storage, each slide was probed in a similar manner to the initial probing. Evaluation was performed using automatic signal count software. Tiles and spots were counted immediately after the initial probing. Reprobed spots for each slide were then compared with the initial probing. RESULTS Slides stored at -20°C and -80°C for 101 days showed the best recovery of probing. CONCLUSIONS Our approach for probe removal and recycling allows repeated examination of even a limited number of slides.
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Affiliation(s)
- Susumu Wakai
- Division of Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
| | - Yasuo Shibuki
- Department of Pathology, National Cancer Center Hospital, Tokyo, Japan
| | - Karin Yokozawa
- Division of Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
| | - Shoko Nakamura
- Division of Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
| | - Yuko Adegawa
- Division of Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
| | - Akihiko Yoshida
- Department of Pathology, National Cancer Center Hospital, Tokyo, Japan
| | - Koji Tsuta
- Department of Pathology, National Cancer Center Hospital, Tokyo, Japan
| | - Koh Furuta
- Division of Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
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Starostová M, Cermák V, Dvořáková M, Karafiát V, Kosla J, Dvořák M. The oncoprotein v-Myb activates transcription of Gremlin 2 during in vitro differentiation of the chicken neural crest to melanoblasts. Gene 2014; 540:122-9. [PMID: 24576577 DOI: 10.1016/j.gene.2014.02.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 02/18/2014] [Accepted: 02/21/2014] [Indexed: 01/09/2023]
Abstract
The neural crest (NC) is a transient dynamic structure of ectodermal origin, found in early vertebrate embryos. The multipotential NC cells migrate along well defined routes, differentiate to various cell types including melanocytes and participate in the formation of various permanent tissues. As there is only limited information about the molecular mechanisms controlling early events in melanocyte specification and development, we exploited the AMV v-Myb transcriptional regulator, which directs differentiation of in vitro chicken NC cells to the melanocyte lineage. This activity is strictly dependent on v-Myb specifically binding to the Myb recognition DNA element (MRE). The two tamoxifen-inducible v-Myb alleles were constructed one which recognizes the MRE and one which does not. These were activated in ex ovo NC cells, and the expression profiles of resulting cells were analyzed using Affymetrix microarrays and RT-PCR. These approaches revealed up-regulation of the BMP antagonist Gremlin 2 mRNA, and down-regulation of mRNAs encoding several epithelial genes including KRT19 as very early events following the activation of melanocyte differentiation by v-Myb. The enforced v-Myb expression in neural tubes of chicken embryos resulted in detectable presence of Gremlin 2 mRNA. However, expression of Gremlin 2 in NC cells did not promote formation of melanocytes suggesting that Gremlin 2 is not the master regulator of melanocytic differentiation.
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Affiliation(s)
- Michaela Starostová
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
| | - Vladimír Cermák
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
| | - Marta Dvořáková
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
| | - Vít Karafiát
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
| | - Jan Kosla
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
| | - Michal Dvořák
- Institute of Molecular Genetics AS CR, v.v.i., Department of Molecular Virology, Vídeňská 1083, Praha 4 142 20, Czech Republic.
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Detection and localisation of the abalone probiotic Vibrio midae SY9 and its extracellular protease, VmproA, within the digestive tract of the South African abalone, Haliotis midae. PLoS One 2014; 9:e86623. [PMID: 24466176 PMCID: PMC3899301 DOI: 10.1371/journal.pone.0086623] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/16/2013] [Indexed: 11/20/2022] Open
Abstract
Probiotics have been widely reported to increase the growth rate of commercially important fish and shellfish by enhancing the digestion of ingested feed through the production of extracellular enzymes such as proteases and alginases. In order to investigate this further, the objective of this study was to localise the bacterial probiont Vibrio midae SY9 and one of the extracellular proteases it produces in the digestive tract of the South African abalone Haliotis midae. This was accomplished by inserting a promotorless gfp gene into the chromosome of the bacterium which was incorporated in an artificial, fishmeal-based abalone feed. In situ histological comparison of abalone fed either a basal diet or the basal diet supplemented with V. midae SY9::Tn10.52 using a cocktail of DNA probes to the gfp gene localised the probiont to the crop/stomach and intestinal regions of the H. midae digestive tract. Generally, the ingested probiotic bacterium occurred in association with feed and particulate matter within the crop/stomach and intestinal regions, as well as adhered to the wall of the crop/stomach. Histological immunohistochemical examination using polyclonal anti-VmproA antibodies localised an extracellular protease produced by V. midae SY9 to the H. midae crop/stomach and intestine where it appeared to be associated with feed and/or other particulate matter in the abalone gut. Thus the data suggests that V. midae SY9 colonises and/or adheres to the mucous lining of the abalone gut. Furthermore, the close association observed between the bacterium, its extracellular protease and ingested feed particles supports the theory that V. midae SY9 elevates in situ digestive enzyme levels and thus enhances feed digestion in farmed abalone.
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38
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Abstract
Tissue transplantation is an important approach in developmental neurobiology to determine cell fate, to uncover inductive interactions required for tissue specification and patterning as well as to establish tissue competence and commitment. Avian species are among the favorite model systems for these approaches because of their accessibility and relatively large size. Here we describe two culture techniques used to generate quail-chick chimeras at different embryonic stages and methods to distinguish graft and donor tissue.
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Affiliation(s)
- Andrea Streit
- Department of Craniofacial Development & Stem Cell Biology, King's College London, London, UK
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39
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Tolosa EJ, Jaurena MB, Zanin JP, Battiato NL, Rovasio RA. In situhybridization of chemotactically bioactive molecules on cultured chick embryo. J Histotechnol 2013. [DOI: 10.1179/2046023612y.0000000008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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40
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Morpholinos: studying gene function in the chick. Methods 2013; 66:454-65. [PMID: 24184187 DOI: 10.1016/j.ymeth.2013.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 09/25/2013] [Accepted: 10/11/2013] [Indexed: 11/21/2022] Open
Abstract
The use of morpholinos for perturbing gene function in the chick, Gallus gallus, has led to many important discoveries in developmental biology. This technology makes use of in vivo electroporation, which allows gain and loss of function in a temporally, and spatially controlled manner. Using this method, morpholinos can be transfected into embryonic tissues from early to late developmental stages. In this article, we describe the methods currently used in our laboratory to knock down gene function using morpholinos in vivo. We also detail how morpholinos are used to provide consistency of the results, and describe two protocols to visualise the morpholino after electroporation. In addition, we provide guidance on avoiding potential pitfalls, and suggestions for troubleshooting solutions. These revised techniques provide a practical starting point for investigating gene function in the chick.
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Wong F, Welten MCM, Anderson C, Bain AA, Liu J, Wicks MN, Pavlovska G, Davey MG, Murphy P, Davidson D, Tickle CA, Stern CD, Baldock RA, Burt DW. eChickAtlas: an introduction to the database. Genesis 2013; 51:365-71. [PMID: 23355415 DOI: 10.1002/dvg.22374] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 12/21/2012] [Accepted: 01/17/2013] [Indexed: 11/12/2022]
Abstract
The precise control of gene expression is critical in embryonic development. Quantitative assays, such as microarrays and RNA sequencing, provide gene expression levels for a large number of genes, but do not contain spatial information. In contrast, in situ methods, such as in situ hybridization and immunohistochemistry, provide spatial resolution, but poor quantification and can only reveal the expression of one, or very few genes at a time. Furthermore, the usual methods of documenting the results, by photographing whole mounts or sections, makes it very difficult to assess the three-dimensional (3D) relationships between expressing and nonexpressing cells. Optical projection tomography (OPT) can capture the full 3D expression pattern in a whole embryo at a reasonable level of resolution and at moderately high throughput. A large database containing spatio-temporal patterns of expression for the mouse (e-Mouse Atlas Project, EMAP, www.emouseatlas.org) has been created, incorporating 3D information. Like the mouse, the chick is an important model in developmental biology and translational studies. To facilitate comparisons between these important model organisms, we have created a 3D anatomical atlas, accompanied by an anatomical ontology of the chick embryo and a database of gene expression patterns during chick development. This database is publicly available (www.echickatlas.org).
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Affiliation(s)
- Frances Wong
- Division of Genetics and Genomics, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
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42
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Fernández J, Fuentes R. Fixation/permeabilization: new alternative procedure for immunofluorescence and mRNA in situ hybridization of vertebrate and invertebrate embryos. Dev Dyn 2013; 242:503-17. [PMID: 23389988 DOI: 10.1002/dvdy.23943] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/26/2013] [Indexed: 11/10/2022] Open
Abstract
A new procedure is described to visualize the spatial pattern of expression of proteins and mRNAs in cryosections or whole-mounted leech, Drosophila, zebrafish, and chick embryos. Our principal contribution is in the use of a nonconventional fixation/permeabilization procedure based on the use of formaldehyde or paraformaldehyde combined with a short C-chain carboxylic acid. Detergents, methanol, and proteinases were omitted. Hybridization procedures were modified from those of routinely used protocols developed for the same embryos. Results showed that cytoskeletal and other cytoplasmic proteins, as well as different mRNAs, were clearly visualized in the expected regions of the embryos. Our procedure has several advantages over currently used protocols: is simpler, produces better general preservation of cells, yields reliable results, and can be used for embryos of different taxa at different developmental stages. It is hypothesized that short C-chain aliphatic carboxylic acids modulate the cross-linking effect of aldehyde fixatives on cell proteins.
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Affiliation(s)
- Juan Fernández
- Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.
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Zhang T, Zhu Q, Xie Z, Chen Y, Qiao Y, Li L, Jing N. The zinc finger transcription factor Ovol2 acts downstream of the bone morphogenetic protein pathway to regulate the cell fate decision between neuroectoderm and mesendoderm. J Biol Chem 2013; 288:6166-77. [PMID: 23319585 DOI: 10.1074/jbc.m112.418376] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During early embryonic development, bone morphogenetic protein (BMP) signaling is essential for neural/non-neural cell fate decisions. BMP signaling inhibits precocious neural differentiation and allows for proper differentiation of mesoderm, endoderm, and epidermis. However, the mechanisms underlying the BMP pathway-mediated cell fate decision remain largely unknown. Here, we show that the expression of Ovol2, which encodes an evolutionarily conserved zinc finger transcription factor, is down-regulated during neural differentiation of mouse embryonic stem cells. Knockdown of Ovol2 in embryonic stem cells facilitates neural conversion and inhibits mesendodermal differentiation, whereas Ovol2 overexpression gives rise to the opposite phenotype. Moreover, Ovol2 knockdown partially rescues the neural inhibition and mesendodermal induction by BMP4. Mechanistic studies further show that BMP4 directly regulates Ovol2 expression through the binding of Smad1/5/8 to the second intron of the Ovol2 gene. In the chick embryo, cOvol2 expression is specifically excluded from neural territory and is up-regulated by BMP4. In addition, ectopic expression of cOvol2 in the prospective neural plate represses the expression of the definitive neural plate marker cSox2. Taken together, these results indicate that Ovol2 acts downstream of the BMP pathway in the cell fate decision between neuroectoderm and mesendoderm to ensure proper germ layer development.
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Affiliation(s)
- Ting Zhang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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Bauer R, Plieschnig JA, Finkes T, Riegler B, Hermann M, Schneider WJ. The developing chicken yolk sac acquires nutrient transport competence by an orchestrated differentiation process of its endodermal epithelial cells. J Biol Chem 2012; 288:1088-98. [PMID: 23209291 DOI: 10.1074/jbc.m112.393090] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
During chicken yolk sac (YS) growth, mesodermal cells in the area vasculosa follow the migrating endodermal epithelial cell (EEC) layer in the area vitellina. Ultimately, these cells form the vascularized YS that functions in nutrient transfer to the embryo. How and when EECs, with their apical aspect directly contacting the oocytic yolk, acquire the ability to take up yolk macromolecules during the vitellina-to-vasculosa transition has not been investigated. In addressing these questions, we found that with progressive vascularization, the expression level in EECs of the nutrient receptor triad, LRP2-cubilin-amnionless, changes significantly. The receptor complex, competent for uptake of yolk proteins, is produced by EECs in the area vasculosa but not in the area vitellina. Yolk components endocytosed by LRP2-cubilin-amnionless, preformed and newly formed lipid droplets, and yolk-derived very low density lipoprotein, shown to be efficiently endocytosed and lysosomally processed by EECs, probably provide substrates for resynthesis and secretion of nutrients, such as lipoproteins. In fact, as directly demonstrated by pulse-chase experiments, EECs in the vascularized, but not in the avascular, region efficiently produce and secrete lipoproteins containing apolipoprotein A-I (apoA-I), apoB, and/or apoA-V. In contrast, perilipin 2, a lipid droplet-stabilizing protein, is produced exclusively by the EECs of the area vitellina. These data suggest a differentiation process that orchestrates the vascularization of the developing YS with the induction of yolk uptake and lipoprotein secretion by EECs to ensure embryo nutrition.
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Affiliation(s)
- Raimund Bauer
- Department of Medical Biochemistry, Medical University of Vienna, Max F. Perutz Laboratories, Dr. Bohr Gasse 9/2, 1030 Vienna, Austria
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AP2γ regulates neural and epidermal development downstream of the BMP pathway at early stages of ectodermal patterning. Cell Res 2012; 22:1546-61. [PMID: 22945355 DOI: 10.1038/cr.2012.122] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Bone morphogenetic protein (BMP) inhibits neural specification and induces epidermal differentiation during ectodermal patterning. However, the mechanism of this process is not well understood. Here we show that AP2γ, a transcription factor activator protein (AP)-2 family member, is upregulated by BMP4 during neural differentiation of pluripotent stem cells. Knockdown of AP2γ facilitates mouse embryonic stem cell (ESC) neural fate determination and impairs epidermal differentiation, whereas AP2γ overexpression inhibits neural conversion and promotes epidermal commitment. In the early chick embryo, AP2γ is expressed in the entire epiblast before HH stage 3 and gradually shifts to the putative epidermal ectoderm during HH stage 4. In the future neural plate AP2γ inhibits excessive neural expansion and it also promotes epidermal development in the surface ectoderm. Moreover, AP2γ knockdown in ESCs and chick embryos partially rescued the neural inhibition and epidermal induction effects of BMP4. Mechanistic studies showed that BMP4 directly regulates AP2γ expression through Smad1 binding to the AP2γ promoter. Taken together, we propose that during the early stages of ectodermal patterning in the chick embryo, AP2γ acts downstream of the BMP pathway to restrict precocious neural expansion in the prospective neural plate and initiates epidermal differentiation in the future epidermal ectoderm.
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High-resolution whole-mount in situ hybridization using Quantum Dot nanocrystals. J Biomed Biotechnol 2012; 2012:627602. [PMID: 22287835 PMCID: PMC3263632 DOI: 10.1155/2012/627602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 09/29/2011] [Accepted: 10/03/2011] [Indexed: 11/23/2022] Open
Abstract
The photostability and narrow emission spectra of nanometer-scale semiconductor crystallites (QDs) make them desirable candidates for whole-mount fluorescent in situ hybridization to detect mRNA transcripts in morphologically preserved intact embryos. We describe a method for direct QD labeling of modified oligonucleotide probes through streptavidin-biotin and antibody-mediated interactions (anti-FITC and anti-digoxigenin). To overcome permeability issues and allow QD conjugate penetration, embryos were treated with proteinase K. The use of QDs dramatically increased sensitivity of whole-mount in situ hybridization (WISH) in comparison with organic fluorophores and enabled fluorescent detection of specific transcripts within cells without the use of enzymatic amplification. Therefore, this method offers significant advantages both in terms of sensitivity, as well as resolution. Specifically, the use of QDs alleviates issues of photostability and limited brightness plaguing organic fluorophores and allows fluorescent imaging of cleared embryos. It also offers new imaging possibilities, including intracellular localization of mRNAs, simultaneous multiple-transcript detection, and visualization of mRNA expression patterns in 3D.
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Pinho S, Simonsson PR, Trevers KE, Stower MJ, Sherlock WT, Khan M, Streit A, Sheng G, Stern CD. Distinct steps of neural induction revealed by Asterix, Obelix and TrkC, genes induced by different signals from the organizer. PLoS One 2011; 6:e19157. [PMID: 21559472 PMCID: PMC3084772 DOI: 10.1371/journal.pone.0019157] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 03/21/2011] [Indexed: 01/19/2023] Open
Abstract
The amniote organizer (Hensen's node) can induce a complete nervous system when grafted into a peripheral region of a host embryo. Although BMP inhibition has been implicated in neural induction, non-neural cells cannot respond to BMP antagonists unless previously exposed to a node graft for at least 5 hours before BMP inhibitors. To define signals and responses during the first 5 hours of node signals, a differential screen was conducted. Here we describe three early response genes: two of them, Asterix and Obelix, encode previously undescribed proteins of unknown function but Obelix appears to be a nuclear RNA-binding protein. The third is TrkC, a neurotrophin receptor. All three genes are induced by a node graft within 4-5 hours but they differ in the extent to which they are inducible by FGF: FGF is both necessary and sufficient to induce Asterix, sufficient but not necessary to induce Obelix and neither sufficient nor necessary for induction of TrkC. These genes are also not induced by retinoic acid, Noggin, Chordin, Dkk1, Cerberus, HGF/SF, Somatostatin or ionomycin-mediated Calcium entry. Comparison of the expression and regulation of these genes with other early neural markers reveals three distinct "epochs", or temporal waves, of gene expression accompanying neural induction by a grafted organizer, which are mirrored by specific stages of normal neural plate development. The results are consistent with neural induction being a cascade of responses elicited by different signals, culminating in the formation of a patterned nervous system.
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Affiliation(s)
- Sonia Pinho
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Pamela R. Simonsson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Katherine E. Trevers
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Matthew J. Stower
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - William T. Sherlock
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Mohsin Khan
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Andrea Streit
- Department of Craniofacial Development, King's College London, London, United Kingdom
| | - Guojun Sheng
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Claudio D. Stern
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
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Nakazawa S, Gotoh N, Matsumoto H, Murayama C, Suzuki T, Yamamoto T. Expression of sorting nexin 18 (SNX18) is dynamically regulated in developing spinal motor neurons. J Histochem Cytochem 2011; 59:202-13. [PMID: 21339182 DOI: 10.1369/0022155410392231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The sorting nexin (SNX) family proteins, which contain a Phox homology (PX) domain, play crucial roles in regulating the intracellular membrane trafficking of the endocytic pathway. The proper coordination of this pathway is important for axonal elongation; however, little is known about the expression and intracellular dynamics of the SNX members during the formation of the nervous system. Here the authors found that SNX18, which belongs to the Src-homology-3-PX-Bin/Amphiphysin/Rvs domain-containing SNX subfamily, was specifically expressed in differentiating motor neurons in the chick and mouse embryonic spinal cord. The expression of SNX18 in embryonic spinal motor neurons was transient and was downregulated as the neurons matured. The authors further demonstrated that the localization of EGFP-SNX18 in growth cones was dynamically regulated and accumulated especially at areas in contact with permissive substrates. These findings collectively suggest that SNX18 may play an active role in axonal elongation.
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Affiliation(s)
- Shiori Nakazawa
- Laboratory of Neuroscience, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Shin M, Alev C, Wu Y, Nagai H, Sheng G. Activin/TGF-beta signaling regulates Nanog expression in the epiblast during gastrulation. Mech Dev 2011; 128:268-78. [PMID: 21402155 DOI: 10.1016/j.mod.2011.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 03/03/2011] [Accepted: 03/07/2011] [Indexed: 01/26/2023]
Abstract
Nanog is required for the maintenance of cellular pluripotency during normal development and in cultured embryonic stem cells. A number of signaling pathways have been implicated in regulating Nanog gene expression in vitro. Using the chick model, we provide in vivo evidence for the involvement of the Activin/TGF-beta signaling pathway in regulating Nanog expression in epiblast cells during gastrulation. Nanog expression in primordial germ cells is not regulated by this pathway, indicating that these two cell types employ different mechanisms for maintaining pluripotency in early development. Furthermore, our data suggest that the bHLH factor E2A plays a role in negatively regulating Nanog expression in vivo. Overall, our data support a direct and positive role of the Smad2/3 mediated TGF-beta signaling pathway in inducing/maintaining Nanog expression.
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Affiliation(s)
- Masahiro Shin
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
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Schlüter B, Gerhards R, Strumberg D, Voigtmann R. Combined detection of Her2/neu gene amplification and protein overexpression in effusions from patients with breast and ovarian cancer. J Cancer Res Clin Oncol 2010; 136:1389-400. [DOI: 10.1007/s00432-010-0790-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 01/14/2010] [Indexed: 11/28/2022]
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